4,506 research outputs found
Progress in the MF radar system at Saskatoon
Two improvements were made to the radar system in the last year, one was the addition of O/X mode capability to the full antenna array used in the real-time wind system, and the other was the development of a coherent receiver. The design of the transmitter antenna is examined. The proposed coherent real-time wind system is also discussed
An electrostatic elliptical mirror for neutral polar molecules
Focusing optics for neutral molecules finds application in shaping and
steering molecular beams. Here we present an electrostatic elliptical mirror
for polar molecules consisting of an array of microstructured gold electrodes
deposited on a glass substrate. Alternating positive and negative voltages
applied to the electrodes create a repulsive potential for molecules in
low-field-seeking states. The equipotential lines are parallel to the substrate
surface, which is bent in an elliptical shape. The mirror is characterized by
focusing a beam of metastable CO molecules and the results are compared to the
outcome of trajectory simulations.Comment: 5 pages, 4 figure
Horizontal wind perturbations and their relation to transient internal gravity waves
Horizontal winds as measured with the Saskatoon MF radar exhibit wind fluctuations which have preferred directions toward north or south in the period range 0 to 60 min at heights between about 60 and 110 km. Longer period perturbations (approx 1-6 h) tend to have an additional maximum of direction frequencies in the E-W sector.The polarization effect analyzed for more than 6 years shows regular changes with season. The main features of the seasonal variations of the direction distributions can be explained by directional filtering of vertically propagating nonstationary gravity waves and appropriate changes of the wave source strength and position in the troposphere. The N-S polarization of the gravity-wave field appears to result in meridional wind reversals with height above the mesopause
A Stark decelerator on a chip
A microstructured array of 1254 electrodes on a substrate has been configured
to generate an array of local minima of electric field strength with a
periodicity of 120 m about 25 m above the substrate. By applying
sinusoidally varying potentials to the electrodes, these minima can be made to
move smoothly along the array. Polar molecules in low-field seeking quantum
states can be trapped in these traveling potential wells. Recently, we
experimentally demonstrated this by transporting metastable CO molecules at
constant velocities above the substrate [Phys. Rev. Lett. 100 (2008) 153003].
Here, we outline and experimentally demonstrate how this microstructured array
can be used to decelerate polar molecules directly from a molecular beam. For
this, the sinusoidally varying potentials need to be switched on when the
molecules arrive above the chip, their frequency needs to be chirped down in
time, and they need to be switched off before the molecules leave the chip
again. Deceleration of metastable CO molecules from an initial velocity of 360
m/s to a final velocity as low as 240 m/s is demonstrated in the 15-35 mK deep
potential wells above the 5 cm long array of electrodes. This corresponds to a
deceleration of almost , and about 85 cm of kinetic energy is
removed from the metastable CO molecules in this process.Comment: 17 pages, 6 figure
Comparison of medium frequency pulsed radar interferometer and correlation analysis winds, part 2
In order to test whether the chosen Doppler peaks represent localized scatters in motion, as opposed to some sort of integrated composite, an attempt was made to determine the change in position of single scatterers over a series of sequential records. A four-antenna system was employed which had 1 degree of freedom in phase. Due to limitations N-S linear transmission and E-W linear reception were used. The Doppler frequency peak selection criteria were that at least two of the four power spectra should have a local peak, and that normalized phase discrepancy, should be less than 0.3. The lack of success in tracking individual scatters seems to suggest a short lifetime. If this is the case, then the present experiment is not able to resolve the difference found between the correlation analysis true velocity and the interferometer value. On the other hand, it appears that the interferometer may be of some use in tracking waves
Measurement of the horizontal velocity of wind perturbations in the middle atmosphere by spaced MF radar systems
Two remote receiving sites have been set up at a distance of approx 40 km from the main MF radar system. This allows measurement of upper atmosphere winds from 60-120 km (3 km resolution) at the corners of an approximately equilateral triangle of side approx 20 km. Some preliminary data are compared through cross correlation and cross spectral analysis in an attempt to determine the horizontal velocity of wind perturbations and/or the horizontal wavelength and phase velocity of gravity waves
Winds and Waves (4 Min - 11 Yrs) in the Upper Middle Atmosphere (60-110 Km) at Saskatoon, Canada (52 Deg N, 107 Deg W): MF Radar (2.2 Mhz) Soundings 1973 - 1983
Examples of gravity waves (GW), tides, planetary waves (PW), and circulation effects in the upper middle atmosphere are presented. Energy densities of GW, tides, and PW are compared. Fourier and spectral analyses are applied to the data
Overcoming “Financial-Phobia”
It’s not uncommon in nursing circles, whether in practice or academe, to see eyes roll back and mouths utter words of anguish when those proposing a solution or new initiative know that leaders will expect solid financial rationale as an integral part of the proposal. For many historical and contextual reasons, nurses and nursing have often shied away from putting serious effort into the development of financial expertise. What is now incredibly clear is that if one expects to be “at the table” influencing key decisions affecting healthcare, then the development of one’s own financial acumen is an imperative. Developing expertise involves both a basic understanding of financial/accounting principles as well as the ability to use financial information to think strategically and realistically about the pros and cons of various decisions. In addition, all leaders need an in depth understanding of how healthcare is reimbursed and which levers can be used to maximize revenues while protecting resources that most ensure the quality and safety of patient care. Many nurses have the desire to learn, but fear the topic and don’t know exactly where to start. This article will outline some practical advice about what to learn and will offer some helpful resources for getting started as well
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